Configuration files

Before editing any configuration files, create a backup. This way, you can revert to a working version in case of problems. Editors like vim and emacs can do this automatically, as well as tools like etckeeper which keep /etc in a version control system (VCS).

List of installed packages

Maintain a list of all installed packages, so that if a complete re-installation is inevitable, it is easier to re-create the original environment.

LUKS headers

Upgrading the system

It is recommended to perform full system upgrades regularly, to enjoy both the latest bug fixes and security updates, and also to avoid having to deal with too many package upgrades that require manual intervention at once. See Pacman#Upgrading packages for details.

Make sure to have the Arch install media or another Linux "live" CD/USB available so you can easily rescue your system if there is a problem after updating. If you are running Arch in a production environment, or cannot afford downtime for any reason, test changes to configuration files, as well as updates to software packages, on a non-critical duplicate system first. Then, if no problems arise, roll out the changes to the production system.

If the system has packages from the AUR, carefully upgrade all of them.

Avoid certain pacman commands

Avoid using the --force option with pacman, especially in commands such as pacman -Syu --force involving more than one package. The --force option ignores file conflicts and can even cause file loss when files are relocated between different packages! In a properly maintained system, it should only be used when explicitly recommended by the Arch developers (see #Read before upgrading the system).

Avoid using the -d option with pacman. pacman -Rdd package skips dependency checks during package removal. As a result, a package providing a critical dependency could be removed, resulting in a broken system.

Partial upgrades are unsupported

Arch Linux is a rolling release distribution. That means when new library versions are pushed to the repositories, the developers and Trusted Users rebuild all the packages in the repositories that need to be rebuilt against the libraries. For example, if two packages depend on the same library, upgrading only one package might also upgrade the library (as a dependency), which might then break the other package which depends on an older version of the library.

That is why partial upgrades are not supported. Do not use pacman -Sy package or any equivalent such as pacman -Sy followed by pacman -S package, always upgrade (with pacman -Syu) before installing a package. Be very careful when using IgnorePkg and IgnoreGroup for the same reason. If the system has locally installed packages (such as AUR packages), users will need to rebuild them when their dependencies receive a soname bump.

If a partial upgrade scenario has been created, and binaries are broken because they cannot find the libraries they are linked against, do not "fix" the problem simply by symlinking. Libraries receive soname bumps when they are not backwards compatible. A simple pacman -Syu to a properly synced mirror will fix the problem as long as pacman is not broken.

The bash script checkupdates, included with the pacman package, provides a safe way to check for upgrades to installed packages without running a system update at the same time. See also BBS##1563725.

Read before upgrading the system

Before upgrading Arch, always read the latest Arch News to find out if there are any major software or configuration changes with the latest packages. Before upgrading fundamental software (such as the kernel, xorg, systemd, or glibc) to a new version, look over the appropriate forum to see if there have been any reported problems.

Act on alerts during an upgrade

When upgrading the system, be sure to pay attention to the alert notices provided by pacman. If any additional actions are required by the user, be sure to take care of them right away. If a pacman alert is confusing, search the forums and the recent news posts for more detailed instructions.

Deal promptly with new configuration files

When pacman is invoked, .pacnew and .pacsave files can be created. Pacman provides notice when this happens and users must deal with these files promptly. Users are referred to the Pacnew and Pacsave files wiki page for detailed instructions.

Also, think about other configuration files you may have copied or created. If a package had an example configuration that you copied to your home directory, check to see if a new one has been created.

Revert broken updates

If a package update is expected/known to cause problems, packagers will ensure that pacman displays an appropriate message when the package is updated. If experiencing trouble after an update, double-check pacman's output by looking at /var/log/pacman.log.

At this point, only after ensuring there is no information available through pacman, there is no relative news on https://www.archlinux.org/, and there are no forum posts regarding the update, consider seeking help on the forum, over IRC, or by downgrading the offending package.

Use the package manager to install software

Pacman does a much better job than you at keeping track of files. If you install things manually you will, sooner or later, forget what you did, forget where you installed to, install conflicting software, install to the wrong locations, etc. Instead, learn how to create a package.

Choose open-source drivers

Always try open source drivers before resorting to proprietary drivers. Most of the time, open source drivers are more stable and reliable than proprietary drivers. Open source driver bugs are fixed more easily and quickly. While proprietary drivers can offer more features and capabilities, this can come at the cost of stability. To avoid this dilemma, try to choose hardware components known to have mature open source driver support with full features. Information about hardware with open source Linux drivers is available at linux-drivers.org.

Be careful with unofficial packages

Use precaution when using packages from the AUR or an unofficial user repository. Most are supplied by regular users and thus may not have the same standards as those in the official repositories. Be careful with AUR helpers which highly simplify installation of AUR packages. Always check PKGBUILDs for sanity and signs of mistake or malicious code before building and/or installing the package.

To simplify maintenance, limit the amount of unofficial packages used. Make periodic checks on which are in actual use, and remove (or replace with their official counterparts) any others. See pacman/Tips and tricks#Maintenance for useful commands.

Update the mirrorlist

Update pacman's mirrorlist, as the quality of mirrors can vary over time, and some might go offline or their download rate might degrade.

Unused packages (orphans)

Old configuration files

Old configuration files may conflict with newer software versions, or corrupt over time. Remove unneeded configurations periodically, particularly in your home folder and ~/.config. For similar reasons, be careful when sharing home folders between installations.

Files not owned by any package

Broken symlinks

Old, broken symbolic links might be sitting around your system; you should remove them. Examples on achieving this can be found here and here.

To quickly list all the broken symlinks of your system, use:

# find . -type l -! -exec test -e {} \; -print

Then inspect and remove unnecessary entries from this list.

Tips and tricks

The following tips are generally not required, but certain users may find them useful.

Use proven software packages

Arch's rolling releases can be a boon for users who want to try the latest features and get upstream updates as soon as possible, but they can also make system maintenance more difficult. To simplify maintenance and improve stability, try to avoid cutting edge software and install only mature and proven software. Such packages are less likely to receive difficult upgrades such as major configuration changes or feature removals. Prefer software that has a strong and active development community, as well as a high number of competent users, in order to simplify support in the event of a problem.

Avoid any use of the testing repository, even individual packages from testing. These packages are experimental and not suitable for a stable system. Similarly, avoid development packages which are built directly from upstream sources. These are usually found in the AUR, with names including things like: "dev", "devel", "svn", "cvs", "git", etc.

Install the linux-lts package

The linux-lts package is an alternative Arch kernel package, and is available in the core repository. This particular kernel version has long-term support (LTS) from upstream, including security fixes and some feature backports. It is useful if you prefer the stability of less-frequent kernel updates or if you want a fallback kernel in case a new kernel version causes problems.

To make it available as a boot option, you will need to update your bootloader's configuration file to use the LTS kernel and ram disk: vmlinuz-linux-lts and initramfs-linux-lts.img.